If you want to whoop some hemi ass, i say go for the ls1. It's not really harder to install, just that it won't go right in like the lt1, but no biggy, get you some mounts and you're set.
The ls1 has a little head start on power, and should move your truck pretty fast.

I would say the whole project could be done for less than 5K.

Really the only fabbing is the mounts and cutting your frame so that the ac compressor will fit.

thanks, keep the questions coming,

allen